Diseases
Erysiphales
Powdery mildew is a fungal disease manifesting as a white web-like coating on plant organs, leading to tissue necrosis, fruit deformation, and significant crop losses.
Mentioned in descriptions 33 570 varieties reference book.
Powdery mildew is caused by ectoparasitic fungi of the order Erysiphales, which develop primarily on the surface of leaves, shoots, and fruits. The initial white web-like coating eventually densifies into "powdery" cushions, upon which fungal fruiting bodies may form as dark spots. As a result of the infection, tissues turn yellow and become necrotic, fruits may crack, and leaves drop prematurely.
The intensity of disease development depends on a complex of factors: high relative humidity, moderate temperatures, the presence of dense canopy, and excessive nitrogen nutrition. Risks increase with alternating dry and wet weather. The harmfulness of the disease is expressed in a reduction of the leaf assimilation area, deterioration of crop quality, and a decrease in the general winter hardiness of crops.
Assessment of variety resistance is conducted under field conditions at various stages of vegetation, most often during the full heading phase. To classify the degree of infection, scoring systems or intensity scales in percentages are used, where varieties with up to 10% infection are considered highly resistant (R), 11 to 40% as moderately resistant (M), and more than 41% as susceptible (S). Variety resistance is ensured by genetic mechanisms that prevent colonization by the pathogen or limit the development of its mycelium.
Selection based on the description text, not official resistance ratings: such data is not available in registers. Mention indicates that the trait is discussed in the variety's sources; see the variety's profile for details on what is specifically stated.
Poa pratensis L. · Kentucky bluegrass
WILLIAM MEYER
Malus domestica (Suckow) Borkh. · Apple
Red Moon, I
Pisum sativum L. · Pea
Paul Degreef
Daucus carota L. · Carrot
Paul Degreef
Rosa L. · Rose
WERNER NOACK
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
VITTEN MATTHIAS D. / FEAR CARLOS D. / PAKOZDI KATALIN
Rubus idaeus L. · Red raspberry
Pisum sativum L. · Pea
W BROTHERTON SEED CO INC
Vaccinium virgatum Aiton · Rabbit-eye blueberry
The New Zealand Institute for Plant and Food Research Limited, The New Zealand Institute for Plant and Food Research Limited
Rosa L. · Rose
Pouw, A.
Malus domestica (Suckow) Borkh. · Apple
Better3fruit NV, Belgium
Malus domestica (Suckow) Borkh. · Apple
Yves Lespinasse, INRA Institut National de la Recherche Agronomique
Malus domestica (Suckow) Borkh. · Apple
Stichting Wageningen Research-Wageningen Plant Research, Netherlands
Rosa L. · Rose
Meilland International S.A.
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Steven D. Nelson Michael D. Nelson Leo W. Stoeckle Daniel S. Nelson
Rosa L. · Rose
DAVID JC AUSTIN
Rosa L. · Rose
DAVID JC AUSTIN
Hordeum vulgare L. · Barley
Saaten Union Recherche (FR)
Hordeum vulgare L. · Barley
SAATZUCHT JOSEF BREUN GMBH and CO.KG
Triticum aestivum L. · Bread wheat
WIERSUM PLANTBREEDING
Triticum aestivum L. · Bread wheat
Nickerson International Research S.N.C.
x Triticosecale Wittm. ex A. Camus · Triticale
Lantmannen SW Seed BV (NL)
Triticum aestivum L. · Bread wheat
Saatzucht Donau, A
Hordeum vulgare L. · Barley
SAATZUCHT JOSEF BREUN GMBH and CO.KG